Court Rules Habitat Must Be Protected After FWS Attempts to Waive Protections for Less Than 40 Sierra Nevada Red Fox

Defenders of Wildlife earned a significant victory for the Endangered Species Act today when a federal district court found that the U.S. Fish and Wildlife Service's decision to not designate critical habitat for the endangered Sierra Nevada red fox was a violation of the law. The U.S. District Court of California granted summary judgment in favor of Defenders, citing that the FWS inappropriately applied a narrow, “not prudent” Endangered Species Act exception when it rejected protecting habitat for this distinct population segment of the fox, which consists of less than 40 individuals in the wild.  

“This case is a blueprint for the future, illustrating that agencies cannot abuse a narrow exception in the law, especially when it comes to the critical needs of an endangered species,” said Daniel Franz, a staff attorney with Defenders of Wildlife’s Biodiversity Law Center. “Every at-risk species requires habitat to survive and ultimately recover, and deserves the full protection the law requires. This ruling makes clear that dodging those requirements is neither acceptable nor permissible.”  

In January 2025, Defenders filed a suit against the FWS for its failure to designate critical habitat when it listed this distinct population segment living on the Sierra crest as endangered under the ESA in 2021. The ESA requires that the FWS designate critical habitat that is essential to the survival and recovery of all federally protected species — threatened and endangered — “to the maximum extent.”  In very limited circumstances, however, the FWS may find that designating critical habitat is “not prudent” but to do so must find there is no benefit from habitat protection to the species.

In today’s decision, the court found that the FWS did not consider:  

• the benefits of designating critical habitat
• the potential effect of critical habitat on the recovery of the species
• that the agency incorrectly determined that habitat loss was not a significant risk to the species

The FWS “not prudent” determination was deemed inappropriate and incorrectly devalued the benefits of habitat protection for the fox.  

“This is more than just a win for the fox —it is a win for every species in a similar situation awaiting critical habitat evaluation. This decision puts meaningful limits on when FWS can avoid designating critical habitat and holds the line of what the ESA itself requires,” said Franz.  

Parties will brief the exact timing and status of the current rule over the coming months. The FWS will make a new determination that properly recognizes the benefit of habitat protection for the fox’s recovery.

The Sierra Nevada red fox is a subspecies of montane red fox with two distinct populations; the population along the Sierra Crest, which experts believe consists of between 18 and 39 individuals; and, the Southern Cascades distinct population segment that lives in the Southern Cascades of Oregon and California. The Sierra Nevada distinct population segment is unique for its alpine characteristics – big “snowshoe” paws, extra-furry winter coats, and small energy-efficient bodies – that let it thrive in the peaks of the Sierra Nevadas when other man-made pressures are not present. Snowmobiling, grazing, and the operation of military training compounds all present habitat-based threats that critical habitat designation would help mitigate.